**Yes with a multimeter and using the microfarad function to check a capacitor maybe nice. But this does not test the capacitor under “load” conditions.**

**Let’s take a look at a typical high voltage circuit of a residential air conditioner or heat pump outdoor unit.**

**Now to do this we will need to get a few measurements.**

**Turn the system on and let the system run for 5-10 mins to stabilize operation.**

**Lets start collecting amp draws and voltages.**

**1st get the amp draw of the fan motor on the brown wire connected to the fan terminal of the capacitor. Example 0.5 Amp**

**2nd**** get the amp draw of the compressor start wire, the blue wire connected to the herm terminal of the capacitor. Example 4.4 Amps**

**3rd** **Now lets get the voltage of the condenser fan motor between the brown wire and yellow common wire at the capacitor. Example 271 Volts**

**4th** **lets get the voltage of the compressor between the blue start wire and yellow common wire at the capacitor. Example 297 Volts**

**Now we can do some math. Here is the formula we will use.** **Use this formula for each component.**

**Some formulas use 2650, 2652, 2654. We will use 2652.**

**Lets do the fan first, 2652 X 0.5 amps / 271 volts = 4.9 mfd **

**Next the compressor, 2652 X 4.4 amps / 297 volts = 39.3 mfd **

**If your capacitor is rated for 40/5 mfd, the readings are within 10% and the capacitor is good.**

**Another Example; if the capacitor is rated 45/5 mfd, an allowable tolerance range for our example is 49.5 mfd – 40.5 mfd. **

**Compressor 2652 X 6.1 amps / 297 volts = 54.5 mfd. This capacitor is performing at 54.5 mfd, which is greater then the 10% tolerance. This capacitor should be replaced.**

**Tech tip the combined average amp draw of the R & C leads from the compressor should equal the amperage of the S lead from the compressor.**

**If not, the capacitor maybe weak and need to be replaced.**

**A weak capacitor can cause the compressor to overheat, causing high discharge temperature which causes a breakdown of the oil lubricant & higher amp draw. The COST OF OPERATION INCREASES! **